1. Field of the Invention
The present invention is related to a method and apparatus for permanently erasing data stored on an optical disc, such as a CD or a DVD.
2. Description of the Related Art
Optical discs include discs such as the CD (Compact Disc) and the DVD (Digital Versatile Disc). These exist in commercial, R (Recordable), and RW (Rewritable)-types. In general, data is stored on an optically reflective foil layer, which is physically supported by a rigid transparent layer, through which a laser beam reads and writes data. The market for CD and DVD recorders and drives has exploded with the growing demand to store digital pictures, video, music, and other data. Optical storage, in turn, creates the need for the capability to erase and/or destroy unwanted or confidential information.
For RW-type discs, erasure may be accomplished by using a recorder or computer drive to re-write over the old information, as disclosed in U.S. Pat. No. 4,816,385 entitled “METHOD OF OPTICALLY RECORDING AND ERASING INFORMATION” to Gravesteijn issued on Mar. 28, 1989; U.S. Pat. No. 6,469,963 entitled “OPTICAL RECORDING MEDIUM AND METHOD OF INFORMATION RECORDING/READING AN OPTICAL RECORDING MEDIUM” to Sawada issued on Oct. 22, 2002; and U.S. Pat. No. 6,709,802 entitled “METHODS AND APPARATUS FOR RENDERING AN OPTICALLY ENCODED MEDIUM UNREADABLE” to Lawandy issued on Mar. 23, 2004. These methods and apparatus involve changing the optical properties of the reflective layer of an RW-type disc, which occurs during a play or record process. Therefore, these methods and apparatus require a computer drive or other recording device in order to erase the contents of the disc.
Furthermore, it may be possible, with the use of sophisticated data recovery and reconstruction methods, to recover data that has been erased on RW-type discs.
For commercial as well as R-type discs, once data is recorded or burned onto the disc, it cannot be erased during a read or write process because of the optically unchangeable foil layer. Sensitive and confidential information, once recorded onto these discs, cannot be simply deleted.
As a result, a need exists for a method and/or apparatus to securely erase commercial, R-type, and RW-type discs that require special handling because they were used to record highly sensitive information.
Once an optical disc becomes useless, the user may break the disc to dispose of it, but the resulting sharp fragments of the broken disc may harm the hands. A compact disc shredder may be used, as described in U.S. Pat. No. 6,676,050 entitled “PAPER SHREDDER HAVING THE FUNCTION OF BREAKING A COMPACT DISC” to Chang issued on Jan. 13, 2004. Such machines, however, are costly and require electric power to operate. Furthermore, their operation generates a great amount of noise in destroying the CDs, and creates waste materials that may require additional disposal measures.
Other existing machines and apparatus demonstrate further shortcomings. The Bosser CD Destroyer (Patent Pending) is a motor-driven machine that dents both surfaces of the optical disc to prevent data retrieval. A dented disc, however, may damage the player if there is an attempt to play the dented disc. In addition, the dents may be smoothed out with commercially available polishing devices and polishes, which can render the disc readable again. Furthermore, this apparatus may not be able to dent through discs with labels applied to them.
Another existing device is the manually operated Disc Peeler™, by Disc Dealer™ (San Diego, Calif.), which features sharp teeth that grind off the reflective foil layer from the compact disc. However, discs that have applied labels would make operation of this device more difficult. Furthermore, this device can generate a great deal of metallic dust, which can be difficult to clean and may be harmful to the user. Obviously, inserting such a frayed disc with metal dust into a playing device could result in damage to the playing device.
Therefore, it is desired to provide a method and device for erasing an optical disc that is inexpensive and simple to operate. It is desirable to have a small, portable device that accomplishes this in a relatively effortless manner without the need for electrical power, and without creating excessive waste material. Finally, the resulting disc should neither pose any harm to the user, nor damage a playing device if there is an attempt to play it.